2022 Fiscal Year Research-status Report
Coherent Control of Atomic Excitation in Strong Fields
| Project/Area Number |
22K03493
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| Research Institution | University of Tsukuba |
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Principal Investigator |
トン ショウミン 筑波大学, 計算科学研究センター, 准教授 (80422210)
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| Project Period (FY) |
2022-04-01 – 2026-03-31
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| Keywords | Atomic excitation / Intense laser / elliptical polarization / highly charged ions |
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| Outline of Annual Research Achievements |
We developed a more effective numerical method to solve the time-dependent Schrodinger equation for arbitrary atoms in an intense laser field.
Since this was the first year of the research project, we focus on not only developing the simulation code, but also rewriting the code so it runs on the newest simulation accelerator, a GPU machine. We also worked on describing a shaped laser pulse or chirp pulse and using a chirped pulse to control atomic dynamical processes. All those progress guarantees that we can perform the proposed research smoothly. Through numerical simulations, we show that the resulting bound-state population is sensitive to both the intensity and the CEP. The experimental data agree with the theoretical prediction, and the results encourage the use of precisely tailored laser fields to coherently control the strong-field excitation process. We find a markedly different behavior for the CEP-dependent bound-state population at low and high intensities with a clear boundary, which we attribute to the transition from the multiphoton to the tunneling regime. This work has been published in Physical Review Letters. This work puts us in a leading position in this research field.
We also collaborated with an experimental group at the University of Electro-Communications to uncover the physical mechanisms which lead to an unexpectedly large polarization of Be-like highly charged ions. This work was also published in Physical Review Letters.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
In the proposal, in the first year, we planned to develop and test the proposed method on a local high-performance workstation with the same architecture as the Cygnus supercomputer. This part has been finished and tested on our local single-node GPU workstation. We also proposed to study the difference between the multiphoton and tunneling processes for atomic excitation in a linearly polarized field using the existing code. This work is the continuation of our collaboration with the experiment group at Griffith University. And the joint work has been published in Physical Review Letters. Of course, we have the necessary research experience and the most simulation tools. Another reason to is that we collaborate with several leading research groups internationally. Therefore, we have the research experience and can access the most recent developments in the field.
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| Strategy for Future Research Activity |
With the newly developed code, we will study the strong field excitation of atoms in a chirped pulse. The main focuses are (1) to study a state-specified excitation in a strong field; (2) to control the atomic photon excitation by tuning the laser pulse shape. Apart from this main research direction, we also work on the hyper-satellite structure of electric x-rays emitted from muonic atomic ions to collaborate with the experimental group in RIKEN and the fundamental interactions in highly charged ions to work with the experimental group in the University of Electro-Communications.
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| Causes of Carryover |
Due to workstation price is higher than we plan then so we do not have fund to buy NAS. We will use it this year.
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[Journal Article] Strong Polarization of a J=1/2 -> 1/2 Transition Arising from Unexpectedly Large Quantum Interference2023
Author(s)
N Nakamura, N Numadate, S Oishi, XM Tong, X Gao, D Kato, H Odaka, T Takahashi,Y Tsuzuki, Y Uchida, H. Watanabe, S Watanabe, and H Yoneda
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Journal Title
Physical Review Letters
Volume: 130
Pages: 113001:1-6
DOI
Peer Reviewed
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[Journal Article] Carrier-Envelope Phase-Dependent Strong-Field Excitation2022
Author(s)
D Chetty, RD Glover, XM Tong, BA deHarak, H Xu, N Haram, K Bartschat, AJ Palmer, AN Luiten, PS Light, IV Litvinyuk, and RT Sang
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Journal Title
Physical Review Letters
Volume: 128
Pages: 173101:1-6
DOI
Peer Reviewed / Int'l Joint Research
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